1. Technical Field
The present invention is directed to sensors for detecting objects using electromagnetic radiation, and specifically to a housing for use with reflective optosensors.
2. Brief Discussion of Related Art
Optosensors are used in a broad range of applications. Typically, optosensors emit electromagnetic radiation, such as infrared (IR) radiation. The radiation emitted can be used to detect the presence or absence of an object in the path of the electromagnetic radiation. When an object is present, the electromagnetic radiation impinges on the object and some of the electromagnetic radiation is reflected back to the sensor. When no object is present, the electromagnetic radiation is not reflected.
While these sensors are typically accurate in detecting the presence or absence of an object, these sensors can be prone to false positives due to particles or contaminants that have accumulated in the path of the electromagnetic radiation. These sensors can detect the particles or contaminants and mistake the particles or contaminants for the object that the sensor is configured to detect, especially where the particles and contaminates are composed of the same or similar material as the object. When these sensors are implemented in a system that depends on accurate detection of objects for proper operation, false positives can have a detrimental affect on the system's operation
In copier applications, optosensors can be used to detect the presence or absence of one or more sheets paper throughout the paper path. In these applications, the operation of the copier can depend on whether a sheet is paper is present or not. For example, sensors can be used to indicate that a paper tray is empty, there is a paper jam, or that a stack of paper in an output tray is at certain height. In these applications, paper dust can accumulate in the path of the IR radiation, which can result in the generation of a signal by optosensor that indicates the presence of a sheet of paper when no sheet of paper is present (i.e. a false positive).